fourlettersuffix =: _4 _3 _2 _1 & {
twoletterprefix =: 0 1 & {

readfile =: 1!:1
writefile =: 1!:2
appendfile =: 1!:3

fn =: < 'input.txt'

data =: readfile fn

NB. parsing data:  ;: data
 box =: ;: data
 first =: > (0 { box)
 second =: > (1 { box)
 third =: > (2 { box)

affix =: 3 : 0
a =. fourlettersuffix y
b =. twoletterprefix y
'fourlettersuffix: ', a, ' twoletterprefix: ', b, ' etc…'
)
